In order to perform harmonic current regulation, a power factor correction (PFC) converter is often added into a power supply. FIG. 1 is a schematic diagram which shows a PFC circuit in the prior art. As shown in FIG. 1, a PFC converter 100 includes a rectifier circuit 101 configured to rectify an alternating-current voltage received from an alternating-current power supply; and a series circuit 102 configured to connect to the rectifier circuit 101, and at least include an inductor 1021 and a switching element 1022.
As shown in FIG. 1, the PFC converter 100 may further include a capacitor C1, a diode D1 and a capacitor C2. As shown in FIG. 1, an input voltage signal (Vin) and an output voltage signal (Vout) can be detected. Furthermore, a current IL flows through the inductor 1021 and flows through the switching element 1022 when the switching element 1022 is on; in addition, a driver signal (Vgs) is provided to control the switching element 1022.
FIG. 2 is a schematic diagram which shows another PFC circuit in the prior art, in which an analog manner is provided. As shown in FIG. 2, the driver signal (Vgs) is provided by an analog controlling circuit 201. The analog controlling circuit 201 at least includes three analog comparator and a multiplier; furthermore, a phase adjustment capacitor 202 and a gain adjustment resistor 203 need to be configured independently in order to perform phase adjustment or gain adjustment. Therefore, the number of components and the cost need to be decreased.
FIG. 3 is a schematic diagram which shows another PFC circuit in the prior art, in which an analog and digital combined manner is provided. As shown in FIG. 3, the driver signal (Vgs) is provided by an analog/digital controlling circuit 301. The analog/digital controlling circuit 301 at least includes a central processing unit (CPU), a pulse width modulation (PWM) circuit and an analog comparator 302; Furthermore, the analog/digital controlling circuit 301 may further include an analog-digital converter (ADC) and a digital-analog converter (DAC).
Compared to the analog controlling manner in FIG. 2, the analog and digital combined manner is provided in FIG. 3. For the analog and digital combined manner, an inductor current IL_1 detected at a switching element 303 is compared with a specified value in the analog comparator 302 to control on/off of the switching element 303.
Reference document 1: US2012/0057382A1
This section introduces aspects that may facilitate a better understanding of the disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.